Vacuum appliance filter assemblies and associated vacuum systems

ABSTRACT

Vacuum cleaner filters, in particular replaceable vacuum cleaner filters suitable for both dry and wet/dry type vacuum cleaners are disclosed, as well as systems incorporating the use of such filters and methods for their use. The filters include a plurality of adjacently positioned pleats arranged in a closed circumferential, cylindrically-shaped path, a top end cap having a central orifice capable of constricting a post on a vacuum filter cage, and optionally a molded end ring oppositely-spaced from the top end cap for engagement with the motor housing of a vacuum cleaner.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 12/243,921, filed Oct. 1, 2008, now U.S. Pat. No.8,206,482, which claims priority to U.S. Provisional Patent ApplicationSer. No. 61/078,362, filed Jul. 4, 2008, the contents of both of whichare incorporated herein by reference in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This disclosure relates generally to filters for vacuum cleaners, andmore particularly to replaceable filters for vacuum cleaners, as well asvacuum appliance systems incorporating and using such filters.

2. Description of the Related Art

Vacuum appliances, in particular vacuum cleaners and wet/dry vacuumcleaners, whether they be strictly relegated to cleaning up drymaterials, or if they are capable of both wet and dry clean up, requiresome method to separate the dust and the dirt from the air that isexhausted back into the surroundings during operation. Typically, vacuumfilters are used in order to prevent debris from re-entering the areabeing cleaned. Hence, filters are commonly used to perform theseseparation functions. Associated with the use of such filters is often aneed to remove and re-attach the filter from the vacuum appliance, forexample, when cleaning the filter or replacing an old or damaged filterwith a new filter. Further, with regard to vacuum cleaners of the typeknown as “wet/dry” vacuum cleaners, the filter is often also removedwhen the vacuum cleaner is suctioning liquids. Consequently, specialstructures often accompany a typical wet/dry vacuum cleaner in order toaccommodate removing and replacing the filter.

With regard to the operation of a vacuum appliance or related air-movingsystem, it is typical that a suction system with a motor creates thevacuum and is mounted in a lid that is removably attached to acollection drum for receiving the vacuumed materials. A portion of thelid, herein termed a mounting assembly, extends at least partiallydownward into the drum and mounts a filter support assembly, commonlyreferred to as a “filter cage,” that generally covers a vacuum intake tothe suction assembly in the lid. The cage can be made of plastic such aspolypropylene, may be generally a cylindrically-shaped molded orextruded part having a series of axial and circumferential support ribswith a large percentage of open surface area to support the filterextended around the cage, and acts (at least in part) to prevent theunwanted radially inward collapse of the filter during vacuum operation.The axial ribs typically align with a longitudinal axis through the cageand the circumferential ribs are often at substantially right angles tothe axial ribs. This type of cage construction creates a relativelystiff component in the axial direction. In addition to supporting thefilter, the cage can provide a safety shield from user access to theimpeller, and may further optionally contain a float or similar devicethat protects the vacuum cleaner from water being inadvertentlysuctioned into the impeller.

The vacuum system inside the lid of the vacuum typically suctionsexternal dirty air or water through a hose into an opening in the drumor lid so that the dirt or water is deposited into the drum. Remainingmaterial, mainly air, then flows radially inward through the filter forremoval of dirt and debris and continues through the cage into a suctionimpeller in the lid, and then is exhausted from the vacuum cleaner.

The filter is commonly attached to the mounting assembly by a threadedstud, or “cage stem”, and nut combination on the end of the cage, whichacts to place the filter in axial compression, utilizing thelongitudinal stiffness of the axial ribs. In typical use, the filter isinserted over the cage, and a mounting flange of rigid material, such asplastic, is attached to the cage or mounting assembly and used tocompress or “sandwich” the filter between the flange and the mountingassembly. The compressive, mechanical force on the entire filter bodyand its filter element is the primary force used to seal the filter tothe vacuum cleaner and prevent unwanted leakage through the vacuumcleaner. Thus, a structurally sound and supportive cage is important tothe overall function of the filter and in general the vacuum cleaner.The filter may also be attached in position by some other method, suchas clamping one or more seals of the filter directly to the mountingassembly or lid. A structurally rigid cage is again necessary to guardagainst entry of unwanted objects, or fingers, into the impeller and tohouse the intake cutoff float.

Experience has shown that while these vacuum filter systems andmechanisms work, they often suffer from being awkward or cumbersome touse, which in turn makes the changing of the filter itself difficult,cumbersome, or time consuming. Further, those vacuum systems wherein thefilter is attached to a mounting assembly by way of a threadedstud-and-nut system on the end of the filter cage, using a threaded nutto retain the filter in a state of axial compression, can be timeconsuming to operate, and the employment of a separate filter nut orsimilar attachment mechanism is undesirable because such parts can bereadily lost or misplaced during the course of filter replacements.Additionally, some of the more complex filter system designs employmechanisms that add unnecessary cost to the overall vacuum applianceproduct. Finally, those filter system designs that do not use or requirefilter retaining mechanisms can often result in the filter becomingreadily dislodged and/or the seal of the filter to the vacuum is brokenwhen the vacuum is dropped or jarred, which in turn can damage both thefilter itself, and cause unwanted leakage of liquid or debris into thevacuum system and motor.

This application for patent discloses filter assemblies for use withvacuum appliances, such as wet/dry vacuum cleaners, which eliminates theneed for any separate retaining mechanism to install the filter to thevacuum appliance, allows the filter to be replaced and/or cleanedquickly and effectively, readily seals to the mounting assembly of thevacuum appliance, remains secure during normal operation withoutunwanted dislodgment from the jarring and rough handling of the vacuumappliance, and which is readily retro-fit to existing vacuum applianceunits already in the marketplace, negating the consumer from having topurchase a new vacuum appliance, such as a new wet/dry vacuum, in orderto use the filter assemblies of the present disclosure.

BRIEF SUMMARY OF THE INVENTION

The inventions described herein are to filter assemblies for use withvacuum appliances, systems including such filter assemblies, and methodsfor attaching such filter and filter assemblies to a vacuum appliance.In accordance with one aspect of the present disclosure, a filter foruse with a wet/dry vacuum appliance is described, wherein the filtercomprises a cap portion having a hole or formed opening extendingtherethrough; a spaced apart annular end ring; and a shaped filterspaced intermediate between the cap and the end ring and extending in aclosed, circumferential path that forms a closed, interior path, whereinthe hole or opening may be circumscribed by a retaining ring, andwherein the cap and the end ring are comprised of an flexible material.The cap may be substantially planar or substantially non-planar, and mayalso include one or more handles for use in improve the ease of removalof the filter assembly from a mounting post or stem of a vacuum filtercage. The annular hole or formed opening may be substantially centrallylocated in the cap portion of the filter assembly, or may be off-setfrom the axial center axis of the cap portion of the filter assembly, asappropriate. Additionally, the filter itself may becylindrically-shaped, oval-shaped, conically shaped, elliptical, orrectangular-shaped, without limitation, and may be pleated ornon-pleated, as appropriate.

In accordance with yet another aspect of the present disclosure, afilter for use with a wet/dry vacuum appliance is described, wherein thefilter comprises a cap having an annular hole or opening extendingtherethrough which may be centrally-located or not; an annular end ring;and a filter positioned intermediate between the cap and the end ringand extending in a circumferential path that forms a closed, interiorpath, wherein the annular hole is circumscribed by a retainingstructure, and wherein the cap and the end ring are comprised of aflexible material bonded to the filter, such that when the cap is inassociation with the wet/dry vacuum appliance, the cap seals on a planebelow the top surface of the filter. In a similarly related aspect ofthe instant disclosure, a filter for use with a wet/dry vacuum applianceis described, wherein the filter comprises a cap having acentrally-located annular hole extending therethrough; an annular endring; and a filter positioned between the cap and the end ring andextending in a closed, circumferential path that forms a closed,interior path, wherein the centrally-located annular hole iscircumscribed by a retaining ring, and wherein the cap and the end ringare comprised of a flexible material bonded to the filter. In furtheraccordance with this aspect of the present disclosure, a filter for usewith a wet/dry vacuum appliance is described, wherein the filtercomprises a cap having a centrally-located opening extendingtherethrough; an annular end ring; and a filter positioned between thecap and the end ring and extending in a circumferential path that formsa closed, interior region, wherein the cap and the end ring arecomprised of a flexible material, such as an elastomeric material,bonded to the filter. In further accordance with these aspects of thedisclosure, the centrally-located opening may be circumscribed by aretaining ring or similar retaining means, wherein the retaining ring iseither integrally formed with the cap, or is not integrally formed withthe cap.

In accordance with another aspect of the present disclosure, a filterassembly for use with a wet/dry vacuum appliance is described, whereinthe filter assembly comprises a cap having a centrally-located openingextending therethrough, and annular end ring, and a filter positionedbetween the cap and the end ring and extending in a circumferential paththat forms a closed, interior region, wherein the cap comprises a stemcover defining an inner region circumscribing the centrally-locatedopening, and wherein the cap and the end ring are comprised of aflexible material bonded to the filter.

In accordance with a further aspect of the present disclosure, a vacuumcleaner system for use in picking up both dry and wet debris using airmovement is described, wherein the system comprises a filter cageassociated with a lid assembly or motor housing of a vacuum cleaner, anda filter assembly. The filter cage assembly comprises a bottom face anda mounting post extending substantially perpendicular to the bottom faceof the filter cage. The filter assembly comprises a cap having acentrally located annular hole extending there through, an annular endring, and a filter spaced intermediate between the cap and the end ringand extending in a closed, circumferential path that forms a closedinterior path and wherein the centrally located annular hole iscircumscribed by a retaining ring which may be integrally formed withthe top face or non-integrally attached to the top face. In accordancewith this aspect of the disclosure, the annular hole has an area lessthan the area of the shaped, leading end of the mounting post, such thatthe annular hole of the filter assembly expands to fit over the shapedleading end of the mounting post as the post is pushed or pulled throughand then contracts once the leading end has passed through, allowing thefilter assembly to be retained in position against the bottom face ofthe filter cage by the integrally-formed retaining ring and theconstriction of the filter hole against the post. Additionally, themounting post of the filter cage may have any number of shapes,including an hour-glass shape, such that the hourglass shape may bedefined by two outer regions and an inner region, the outer regionshaving a diameter greater than the diameter of the inner region, andwherein such a shaped mounting post acts to enhance the seal of filterassemblies against the filter cage. In further accordance with thisaspect of the present disclosure, as a system, the filter assembly fitsover the top of the filter cage and the mounting post extends at leastpartially through the centrally-located opening in the cap of thefilter, and is retained in position by an integrally-formed retainingring on the cap, wherein the centrally-located opening has anuncompressed diameter smaller than a diameter of a portion of themounting post such that, during assembly, the centrally-located openingexpands in diameter to fit over a portion of the mounting post, andthereafter contracts in diameter so as to retain the filter over thefilter cage.

In accordance with another aspect of the present disclosure, a vacuumcleaner system is described, wherein the system comprises a filter cagecomprising a top face, a bottom face opposite the top face, and amounting post extending substantially perpendicular to the bottom faceof the filter cage; and a filter assembly comprising a cap having anopening extending therethrough, an annular end ring, and a filterpositioned between the cap and the end ring and extending in a closed,circumferential path that forms a closed interior path, wherein theopening in the cap is circumscribed by an elastomeric material, whereinthe filter assembly fits over the top of the filter cage and a portionof the mounting post extends through the opening in the cap of thefilter assembly and is retained in position by the elastomeric material,and wherein the opening in the cap has an uncompressed diameter smallerthan the diameter of a portion of the mounting post, such that duringassembly the opening expands in diameter to fit over the portion of themounting post, and thereafter contracts in diameter to retain the filterassembly over the filter cage.

In accordance with a further aspect of the present disclosure, a wet/dryvacuum cleaner is described, which comprises a filter cage including aprojection extending therefrom, the filter cage having a length; and afilter assembly which includes a cap formed of deformable material thatdefines an opening, and, a filter extending from the cap, wherein thefilter has a length that is longer than the length of the filter cage;wherein the filter is coupled to the cage by positioning the filterabout the cage such that the length of the filter extends along thelength of the cage and such that the projection from the filter cageextends through the opening of the filter cap such that the filter isretained in place at least in part by compressive forces resulting fromthe compression of the deformable material that defines the openingbeing applied against the projection; and wherein the engagement of theprojection with the opening causes a deformation of the deformablematerial such that the cap assumes a substantially conical shape. Infurther accordance with this aspect of the disclosure, the filter cagemay be attached to a motor housing of a vacuum appliance, wherein theconical shape formed by the deformed material is such that the point ofthe cone points in a direction towards the motor housing. In stillfurther accordance with this aspect of the disclosure, when the filtercage is attached to a motor housing of a vacuum appliance, the conicalshape formed by the deformed material is such that the point of the conepoints in a direction extending away from the motor housing.

In a further aspect of the present disclosure, an apparatus, such as avacuum apparatus or the like, is described, wherein the apparatuscomprises a filter cage that includes a first end and a second end and amounting projection extending from the second end; and, a filterassembly including a filter extending about the filter cage, the filterincluding a first end and a second end, a mounting cap positioned at thesecond end of the filter, the mounting cap being at least partiallyformed of flexible material and defining an opening; wherein themounting projection extends through the opening defined by the mountingcap such that the mounting cap engages a region of the mountingprojection; and wherein the distance from the first end of the filtercage to the region where the mounting cap engages the mountingprojection is less than the distance from the first end of the filtercage to the second end of the filter assembly.

In another aspect of the present disclosure, a method of attaching afilter to the filter cage of a wet/dry vacuum is described, wherein themethod comprises the steps of providing a filter cage that includes afirst end and a second end and a mounting projecting extending from thesecond end, the mounting projection defining a mounting region;providing a filter assembly including a first end, a second end, and amounting cap positioned at the second end of the filter, the mountingcap being at least partially formed of a deformable material anddefining an opening; positioning the filter assembly about the filtercage such that the filter assembly fits over the filter cage and suchthat the second end of the filter assembly is positioned closer to thesecond end of the filter cage than to the first end of the filter cage;and deforming the mounting cap to cause the mounting projection toextend through the opening in the end cap and to cause the end cap toengage the mounting region of the mounting projection.

In accordance with a further aspect of the present disclosure, a filterassembly for use with a wet/dry vacuum appliance is described, whereinthe filter assembly comprises a generally cylindrical filter comprisingpleated material, the filter defining a first end; and a mounting capcoupled to the first end of the filter, the mounting cap defining agenerally cylindrical opening near the center of the mounting cap and aring extending about the opening, wherein the mounting cap has anelastomeric characteristic that allows the mounting cap to be deformedto take a substantially conical shape, and wherein the ring has anelastomeric characteristic that allows the ring to be deformed such thatit exerts compressive forces radially inward towards the center of thecylindrical opening.

In a further aspect of the present disclosure, a filter assembly for usein a wet/dry vacuum that includes a mounting element is described,wherein the wet/dry filter assembly comprises a filter means forfiltering particulate matter collected by the wet/dry vacuum, andelastomeric retention means for creating compressive forces tending toretain the filter assembly in a fixed position with respect to a pointon the wet/dry vacuum when at least a portion of the mounting element ispositioned within an opening formed in the elastomeric retention means.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The following figures form part of the present specification and areincluded to further demonstrate certain aspects of the presentinvention. The invention may be better understood by reference to one ormore of these figures in combination with the detailed description ofspecific embodiments presented herein.

FIG. 1 illustrates a perspective view of an exemplary vacuum appliancesystem associated with the vacuum filters of the present disclosure.

FIG. 2 illustrates a perspective view of an exemplary vacuum filter ofthe present disclosure.

FIG. 3 illustrates a side elevational view of the vacuum filter of FIG.2.

FIG. 4 illustrates a bottom view of the exemplary vacuum filter of FIG.2.

FIG. 5 illustrates a perspective cross-sectional view of the filter ofFIG. 2, taken along line 5-5.

FIG. 6 illustrates a perspective view of an exemplary filter accordingto one embodiment of the present disclosure, shown in explodedorientation above a suction unit of a conventional wet/dry vacuum.

FIG. 7A illustrates a cross-sectional schematic view of an exemplaryvacuum cleaner mounting assembly with a filter of the present disclosuremounted thereto.

FIG. 7B illustrates a cross-sectional schematic view of an alternativevacuum cleaner mounting assembly with a filter of the present disclosuremounted thereto.

FIG. 7C illustrates a cross-sectional schematic view of a furtheralternative vacuum cleaner mounting assembly with a filter of thepresent disclosure mounted thereto.

FIG. 8 illustrates a perspective view of an alternative vacuum filterassembly of the present disclosure.

FIG. 9 illustrates a perspective view of a further alternative vacuumfilter assembly of the present disclosure.

FIG. 10A illustrates a side, cross-sectional view of the filter of FIG.9, taken along line 9-9.

FIG. 10B illustrates a top view of the filter of FIG. 9.

FIG. 11 illustrates a perspective view of a further alternative filterassembly of the present disclosure.

FIG. 12A illustrates a side, partial cut-away view of a filter cageassembly for use with the present disclosure, showing a retro-fit ofprior cages assemblies.

FIG. 12B illustrates a side, partial cut-away view of an alternativefilter cage assembly for use with the present disclosure, showing aretro-fit of a cage assembly.

FIG. 12C illustrates a partial, perspective view of the bottom face andmounting post of a further alternative filter cage assembly for use inaccordance with the present disclosure.

FIG. 12D illustrates a partial, perspective view of the bottom face andmounting post of an alternative filter cage assembly for use inaccordance with the present disclosure.

FIG. 12E illustrates a cross-sectional view of the filter cage assemblyof FIG. 12D, taken along line 12-12.

FIGS. 13A-E illustrate various alternative embodiments of the presentdisclosure.

FIG. 14A illustrates a further filter assembly in accordance with thepresent disclosure.

FIG. 14B illustrates a cross-sectional view of the filter assembly ofFIG. 14A, taken along line 14-14.

FIG. 15 illustrates a perspective view of an exemplary filter assemblyin accordance with the present disclosure.

FIG. 16 illustrates a perspective view of an exemplary filter assemblyin accordance with the present disclosure.

While the inventions disclosed herein are susceptible to variousmodifications and alternative forms, only a few specific embodimentshave been shown by way of example in the drawings and are described indetail below. The figures and detailed descriptions of these specificembodiments are not intended to limit the breadth or scope of theinventive concepts or the appended claims in any manner. Rather, thefigures and detailed written descriptions are provided to illustrate theinventive concepts to a person of ordinary skill in the art and toenable such person to make and use the inventive concepts.

DETAILED DESCRIPTION

The Figures described above and the written description of specificstructures and functions below are not presented to limit the scope ofwhat Applicants have invented or the scope of the appended claims.Rather, the Figures and written description are provided to teach anyperson skilled in the art to make and use the inventions for whichpatent protection is sought. Those skilled in the art will appreciatethat not all features of a commercial embodiment of the inventions aredescribed or shown for the sake of clarity and understanding. Persons ofskill in this art will also appreciate that the development of an actualcommercial embodiment incorporating aspects of the present inventionswill require numerous implementation-specific decisions to achieve thedeveloper's ultimate goal for the commercial embodiment. Suchimplementation-specific decisions may include, and likely are notlimited to, compliance with system-related, business-related,government-related and other constraints, which may vary by specificimplementation, location and from time to time. While a developer'sefforts might be complex and time-consuming in an absolute sense, suchefforts would be, nevertheless, a routine undertaking for those of skillthis art having benefit of this disclosure. It must be understood thatthe inventions disclosed and taught herein are susceptible to numerousand various modifications and alternative forms. Lastly, the use of asingular term, such as, but not limited to, “a,” is not intended aslimiting of the number of items. Also, the use of relational terms, suchas, but not limited to, “top,” “bottom,” “left,” “right,” “upper,”“lower,” “down,” “up,” “side,” and the like are used in the writtendescription for clarity in specific reference to the Figures and are notintended to limit the scope of the invention or the appended claims.

In general terms, Applicants have created filter assemblies for use withvacuum appliances, such as wet/dry vacuum cleaners, which eliminate theneed for separate retaining mechanism to install the filter to thevacuum appliance, allows the filter to be replaced or cleaned quicklyand effectively, seals automatically to the mounting assembly of thevacuum appliance, remains secure during normal operation withoutunwanted dislodgment from the jarring and rough handling of the vacuumappliance, and which is readily retro-fit to existing vacuum cleanerunits already in the marketplace.

Turning now to the figures, FIG. 1 illustrates a schematic, perspectiveview of an exemplary vacuum appliance system 10 for use with the filtersystems of the present disclosure, wherein the system shown is a wet/dryvacuum appliance 20 comprising a collection drum or chamber 30, casters42 mountable on the bottom end 32 of the drum 30, and a lid 50 removablyattached to top end 34 of the collection drum 30 containing a powerhead.The lid 50 is removably attached (e.g., via a hinge mechanism or thelike, or via completely lifting off from the top of drum 30 by releasinglatches 54) to the collection drum 30 so that the lid can be readilyremoved so as to empty debris or liquids contained with in the drum, oras relates to the present disclosure, to change or clean the filterassembly (not shown) that is typically mounted in association with theunderside of a motor housing, powerhead, or lid of the vacuum appliance.As with most known wet/dry vacuum cleaners, a motor (not shown) isgenerally coupled to the mounting assembly on the inside portion of lid50 of the vacuum cleaner 20, which is operable to create the vacuuminside the collection drum 30 so as to draw solid debris, liquid, orboth into the collection drum 30 through an inlet port 60 by way of avacuum hose (not shown). The collection drum 30 may also optionallyinclude a drain 40 so that liquid within the drum can be emptied (e.g.,via a pump such as that described in U.S. Design Patent No. D551,681)and removed without having to undo and remove the lid 50. Vacuumappliances such as the system 10 generally include a filter assembly aswill be described herein, as well as a mounting assembly and/or a filtercage (not shown) which will be described in more detail herein, andwhich is typically coupled to or integrally formed with the underside ofthe lid 50 or motor housing, extending downwardly into collection drum30.

The vacuum appliance itself, including the collection chamber/drum 30and the lid and powerhead 50 may be made of any number of lightweight,relatively inexpensive plastics or polymers of suitable strength andrigidity, including but not limited to polypropylene, polyurethane, andother similar materials. The motor frame and other select parts of thegeneral vacuum assembly may be made of a material more rigid and havinga smaller flex modulus than that comprising the collection chamber,exemplary materials including but not being limited to glass-filledpolyester, glass-filled polycarbonate, thermoset polyester, and similarpolymeric materials, all of which are heavier, and often more expensive,than the material used to make the collection chamber.

FIGS. 2-5 illustrate a filter assembly 100 in accordance with aspects ofthe present disclosure. In FIG. 2, a perspective view of filter assembly100 is illustrated, which comprises an integrally-formed an integratedcap section 110, an end ring 130 (not shown), and, a generallycylindrically-shaped, pleated filter 120 intermediate between cap 110and end ring 130 and extending in a closed, circumferential path andwhich includes and forms a closed, interior region. The integrated cap110 may further, optionally comprise two integrally-formed handleportions 112, 114 as shown, and a formed hole 118 in the center of thecap, centrally-formed hole 118 extending from the top surface 111 of cap110 through the cap to the closed, interior airflow path formed byfilter 120. The cap 110 may also optionally comprise a plurality ofintegrally-formed support struts 115, to add structural integrity to thecap section 110. As shown in the figure, the handle portions 112 and 114may be substantially diametrically opposed in orientation, and canextend partially over the top and edges of the pleated filter 120, so asto allow for providing the user with a gripping surface to aid in filterremoval from the filter cage of a vacuum appliance when changingfilters. While two handle-portions 112 and 114 are illustrated, it willbe recognized that the filter assemblies described herein may have nohandles, a single handle, or more than two handles, which may beoriented in a variety of manners, such as perpendicular to the top faceof the cap portion, without limitation As also illustrated in FIG. 2,the hole 118 in cap 110 can be circumscribed by an integrally- ornon-integrally formed annular retaining means, such as retaining ring116 having a general taurus-like (donut) shape of such a size, shape andinternal diameter that the ball or end flange on the leading end ofmounting shaft on a vacuum's filter cage can be forced up and throughthe hole 118 as will be discussed in more detail below, so as to retaina filter assembly of the present disclosure on the filter cage andseated against the base of the vacuum appliance. If retaining ring 116is integral, it will be formed into cap 110 as part of the manufacturingprocess. In the event that ring 116 is non-integral and is a separateelement of the filter assembly, it may be attached to the top surface111 through any number of appropriate chemical (e.g., glue) ormechanical methods, without limitation.

FIG. 3 illustrates a side view of filter assembly 100, showing inparticular the dimensional relationships between the integrated cap 110,the filter 120, and the end ring 130. As shown therein, in onenon-limiting, exemplary aspect of the disclosure, the integrated topmounting cap 110 has an outer diameter d₁ which is equal in allorientations, due the substantially circular shape of cap 110. Filter120, which is integrally attached to cap 110, has an outer diameter d₃.In accordance with this non-limiting, exemplary aspect of the presentdisclosure, the outer diameter d₃ of filter 120 can be greater than theouter diameter d₁ of cap 110. As illustrated, only the formed handles112, 114 extend outwardly in such a manner as to extend over the outeredge of filter 120, such that the diameter d₂ between the outer edges ofthe handles is greater than the outer diameter d₃ of filter 120.However, viewing FIG. 2 in combination with FIG. 3, it will be notedthat in accordance with certain aspects of the disclosure, the majorportion of cap 110 circumscribes the top end of filter 120, such thatmore than 50% of the outer diameter d₁ of cap 110 is less than outerdiameter d₃ of filter 120. In accordance with exemplary, non-limitingaspects of the present disclosure, the diameter d₁ of greater than 50%of the cap 110 to the outer diameter d₃ of filter 120 has a ratioranging from about 1.0:1.1 to about 1.0:2.0, inclusive, preferablyranging from about 1.0:1.1 to about 1.0:1.5, or further preferablyranging from about 1.0:1.2 to about 1.0:1.4. Additionally, and by way ofnon-limiting example only, the ratio between outer diameter d₁ and theheight h₁ of filter 120 may be in ratio ranging from about 1.0:1.3 toabout 1.0:1.8, preferably from about 1.0:1.4 to about 1.0:1.6. Finally,as illustrated in FIG. 3, the integrally-formed end ring 130 has anouter diameter d₄ that is less than the outer diameter d₃ of filter 120,and is substantially equal to the outer diameter d₁ of cap 110. In anexemplary, non-limiting aspect, a filter assembly 100 may have a filterheight h₁ of about 8.25 inches, a filter outer diameter d₃ of about 6.5inches, and cap 110 and end ring 130 diameters of about 5.38 inches,with the diameter d₂ spanning handle portions 112, 114 being about 7.5inches. As indicated above, however, these dimensional relationships arenot limiting, and it is equally acceptable for the cap 110 and/or endring 130 to have an outer diameter greater than that of the outerdiameter of the filter 120, or alternatively substantially equal to theouter diameter of the filter 120. Additionally, in accordance withcertain aspects of the present disclosure, annular end ring 130 need notbe included in the filter assembly in order to provide support at thebottom end of the filter, or to aid in providing a sealing surfaceagainst the motor housing of a vacuum appliance. In such instances,support for the filter assembly may be accomplished through theinclusion of an internal support web or mesh, such as a metal meshsupport assembly (not shown), which circumscribes the interior region ofthe filter 120.

In FIG. 4, a bottom view of the vacuum filter assembly of FIG. 2 of thepresent disclosure is shown. As seen in the figure, hole 118 extendsthrough annular retaining ring 116 on the top surface 111 of cap 110 tobottom face 113 of cap 110. FIG. 4 also illustrates the closed, interiorpath of filter 100 formed by the circumferential path of filter 120.This interior path is the portion of the filter assembly which, intypical use, is fit over the filter cage of a vacuum appliance,whereupon the leading end of the mounting shaft extends up and throughcentral hole 118, as will be described in more detail with reference toFIG. 6 and FIG. 7.

FIG. 5 illustrates a perspective cross-sectional view of an exemplaryfilter 100 of the present disclosure as illustrated in FIG. 2, takenalong line 5-5, and showing the filter seals, filter element, and cap110. As is more clearly seen in this view, the outer edges of the filterelement 120 extend past the outer edge, or diameter, of both theintegrated end cap 110 and the annular end ring 130, save for portionsof handles 112 and 114 integrally formed with end cap 110, which have alip 117 to enhance the grip for the user and which extends a distancedown and over the outer edge of the filter element 120. The plurality ofintegrally-formed support struts 115 on the top surface 111 of cap 110act to add strength to the end cap 110 and provide additional mechanicalsupport to the filter assembly during typical operation and assembly incombination with a filter cage of a vacuum appliance, which will bedescribed in more detail below.

The end cap 110, as well as the integrated end ring 130, may be madefrom any conventional rigid or semi-rigid material having a flexibilitygreat enough to go over the “ball” or equivalent shaped structure 82 onthe leading end of the stem 80 of the filter cage 90 and form a seal, asillustrated in FIG. 6, including but not limited to plastics andpolymers such as polyvinyl chloride (PVC), metals such as steel, andelastomeric materials that are suitable for absorbing energy and forminga retaining seal, particularly under vacuum conditions, such materialsincluding but not limited to polyurethane elastomers and the like. Theterm “elastomer”, or “elastomeric”, as used herein, refers generally tocompositions or materials that have a glass transition temperature,T_(g), at which there is an increase in the thermal expansioncoefficient, and includes both amorphous polymer elastomers andthermoplastics. Specifically preferred for use herein are elastomerswhich have low T_(g)'s, e.g., below 600° F. (315.5° C.), densities (orspecific gravities) less than about 50 lb/ft³, and tensile strengthsranging from about 10 PSI (about 68,947.572 Pa) to greater than about100 PSI (about 689,475.728 Pa). This includes but is not limited topolyolefin elastomers, polyurea elastomers, polyurethane elastomers,latexes, and thermoplastic compounds/elastomers. As used herein, theterm “elastomer” or “elastomeric compound” may also include silicone- orsilica-based elastomers, or silicone-containing elastomers or rubbers.Exemplary elastomers and rubbers compounds which may be used in formingthe filter assemblies described herein include but are not limited toacrylonitrile-butadiene rubbers (NBR) such as Buna-N, hydrogenatednitrile rubbers, ethylene-propylene elastomers, fluorocarbon rubberssuch as VITON®, chloroprenes, silicone rubbers and elastomers,fluorosilicone rubbers and elastomers, polyacrylate elastomers, ethyleneacrylic elastomers, styrene-butadiene rubbers (SBR), polyurethanesincluding both polyester and polyether urethanes, and natural rubbers(NR).

In particular, in accordance with one aspect of the present disclosure,the end cap 110 and the end ring 130 are comprised of an elastomericmaterial, preferably a polyurethane foam, and more particularly it istwo-part polyurethane foam, such as those two-part polyurethane foamsthat comprise a mixture of an isocyanate and a resin. In accordance withcertain aspects of the present disclosure, the two-part polyurethanefoam may be made of the Elastoflex™ material manufactured by BASFCorporation of Livonia, Mich. Exemplary, non-limiting two-partpolyurethane foams have a mix ratio of between about 1:1 and about 3:1,resin to isocyanate, this ratio being inclusive. Suitable, alternativeelastomers which may be used to form one or both of the cap 110 and theend ring 130 include but are not limited to polyurethane (commercialexample including Lupranat®, Lupranol®, Lupraphen®, Elastoflex®, andCellasto®), expandable polystyrene (EPS; commercial examples includingStyropor® and Neopor®, both expandable polystyrene (EPS) materialsavailable from BASF), extruded polystyrene (XPS; commercial examplesincluding Styrodur® C or Peripor® from BASF), melamine resin (such asBasotect®), or polypropylene (such as Neopolen P®).

The elastomeric materials used to manufacture both the integrated endcap 110 and the integrated end ring 130 are preferably of the same type,and further have a variety of physical and mechanical properties thatallows the overall filter assemblies disclosed herein to perform in theadvantageous manner described. Exemplary characteristics of the materialinclude density, tear resistance, elongation, set compression, shore “A”hardness, tensile strength, hardness, static modulus, and resistance toa number of organic solvents due to the crosslinking structure of theelastomeric material, among other features. Exemplary, non-limitingphysical and mechanical property ranges are shown in Table 1, as well asexemplary (non-limiting) measurement standards which may be used toobtain data for the listed physical and/or mechanical properties of theelastomeric materials. In accordance with the present disclosure, theelastomeric materials used to form both the integrated end cap 110 andthe end ring 130 may have two or more physical characteristics orproperties as set forth in Table 1, such as tensile strength,elongation, and closed cell content.

TABLE 1 Physical and Mechanical Characteristics of elastomeric materialssuitable for use in forming portions of filter assemblies of the presentdisclosure. Exemplary Range Physical/Mechanical Property MeasurementStandard Values¹ Density ASTM D1564, D1622 16-25 lb/ft² TensileStrength³ ASTM D1564, D412 150-220 psi Elongation ASTM D1564, D41290-200% Tear Resistance, Die “C” (PLI) ASTM D624-00(2007) 20-40Compression Set ASTM D1564/D3576 11-70% Shore “A” Hardness (free riseISO 7619 30-40 pts. molded) ASTM D1415, D2240 Closed Cell Content ASTMD-2856 80-99% Dielectric Strength² ASTM D149-97a 20-100 kV/in. ¹Allvalue ranges temperature required by the listed test standard.²Dielectric strength is the measure of the ability of an elastomer toresist current flow when voltage is applied. ³As used herein, the term“tensile strength” refers to the maximum amount of tensile stress thatcan be applied to the elastomeric material before it ceases to beelastic, measured in units of force per unit area (N/m² or Pa) accordingto ASTM-standard D-638, ASTM D-412, or ISO 37 (available from the worldwide web at astm.org).

The filters, such as filter 120, suitable for use in the filterassemblies of the present disclosure may be of the pleated type asillustrated, or may be non-pleated, and may be made of any number ofsuitable filtration materials, including but not limited to paper;cloth; glass-fiber materials; split-fiber materials; solution-spunfibers and materials made from such fibers; felt materials; naturalfiber filter material; expanded polytetrafluoroethylene (PTFE)membranes; expanded ultra high molecular weight polyethylene (PE)membranes and materials; melt-blown media, such as melt-blownpolypropylene (PP) or melt-blown polyethyelene (PE); microporous opencell polymers, such as polyurethane foam; poly(ethylene terephthalate),(PET) or polyphenylene sulfide (PPS) based materials, as well ascopolymer-based materials thereof; HEPA-type materials and related fiberor randomly-arranged fiber materials (high-efficiency particulate air(HEPA) filters being those filters which can remove at least 99.97% ofairborne particles 0.3 micrometers (μm) in diameter) in accordance withNIOSH requirements; triboelectrified media and materials, and the like,any of which may be treated so as to be hydrophobic and/or have mold andmildew preventative characteristics. Such treatments may be especiallydesirable for those filter assemblies manufactured for use in wet/dryvacuum cleaners. Filter 120 may be folded or pleated, as illustrated inthe figures, e.g., FIG. 2, or it may be non-folded, as appropriate.Preferably, in accordance with one aspect of the present disclosure, andregardless of which material is used to form filter 120, the filtermaterial is folded into multiple pleats and formed into a generallycylindrical or tube-like shape having a “rippled” or “pleated”appearance, so as to increase the exposed surface area. This foldingincreases the area of the filter that is in contact with the airstreamduring vacuum appliance operation, thus effectively improving thefiltration without decreasing the airflow. The filters may also have avariety of porosities, or pore size distributions, depending upon thedesired air flow permeability to be achieved. Exemplary porositiesinclude, but are not limited to, about 1 micron, about 3 micron, andabout 10 microns, as well as porosities greater than or less than thesevalues, e.g., about 0.1 microns, and about 15 microns. Such porosityvalues, as used herein, mean that the filter will stop at least 99% ofall particles that are of the target particle size (e.g., 10 microns) orlarge. Porosity measurements can be by any appropriate measurementmethod or device, such as with a Coulter Porometer™ (CoulterElectronics, Inc., Hialeah, Fla.), or using industry standard testingmethods, such as ASTM F316-03 (available from the American NationalStandards Institute). Such porosities result in filters according to thepresent invention having air flow permeabilities ranging from about 2cfm/ft² to about 80 cfm/ft². In general, however, the filters 120 arerelatively stiff and simultaneously flexible in nature in order to holdtheir shape, and will have a porosity as desired in order to filter drymaterials, such as dust, drywall dust, dirt, fireplace ashes, and thelike out of an air stream during operation of the vacuum cleaner whileallowing air t flow through it to an outlet through the vacuum lid.

As indicated, the filters of the present disclosure may also optionallyfurther comprise one or more biostatic and/or biocidal agents. Suitablebiostatic or biocidal agents are typically selected to havebacteriostatic and/or fungistatic properties which may be used to treatthe filters of the present disclosure and reduce biologic contamination(e.g., mycotoxin contamination) of the air passing through the vacuumappliance and using such a filter. Exemplary biostatic and/or biocidalagents which may be used for this purpose include but are not limited to2-bromo-2-nitropropane-1,3-diol, isothiazolines, methyl or propyl orbutyl parahydroxybenzoates, sorbic acid, benzoic acid and salts of theseacids, phenoxy ethanol, triclosan, diclosan, dichlorophen, chlorhexidinegluconate, orthophenylphenol, quaternary biocides,orthobenzylparachlorophenol, and substituted diphenyl ethers, as well ascombinations thereof. In order to enhance the application or use of suchbiological inhibitors, a number of additional additives may be appliedto the filter, or combined with the biocidal or biostatic agents appliedto the filter, including but not limited to humectants, rheologicaladditives, and surfactants. The humectant may be selected from calciumchloride, glycerol, sorbitol, ethylene glycol, polyethylene glycol(PEG), propylene glycol, 1,3 butylene glycol, sodium sulphate, sodiumchloride and sodium dioctylsulphosuccinate. The rheological additive istypically a thickening agent, a gelling agent or a viscosity modifier,and may be one or more compounds selected from sodiumcarboxymethylcellulose (CMC), hydroxyethylcellulose (HEC),hydroxypropylcellulose (HPC), polyethylene glycols, polypropyleneglycols, polyvinyl alcohol, polyvinyl acetate (PVA),polyvinylpyrrolidone and copolymers of these, hydroxypropyl guar,xanthan gum, chitosan, acrylated copolymers, polyacrylic polymers(carbopols) and water soluble polymers, as well as combinations thereof.Preferably, the composition remains effective, in service, for periodsof 6 months or more, such that the filter, after 3 months in normal use,produces at least log 1 reduction in cfu's/gram of clean filter materialin comparison with an untreated filter under the same conditions.

Additionally, while the filter assemblies described herein have beenillustrated and described generally with reference to a cylinder-shapedassembly, it is envisioned that these filter assemblies may be of anynumber of other suitable shapes, including but not limited to oval-typecylinder, conical, elliptical, square, rectangular, and hexagonal.

An exploded view of a filter assembly 100 in association with the filtercage assembly of a typical vacuum appliance is illustrated in FIG. 6,wherein the filter cage 90 forms a part of the suction unit 70 which isoften an integral part of vacuum lid 50 and mounts on the top of avacuum appliance collection drum 30 (see, FIG. 1) for collecting debrisin the form of dirt, dust, saw dust, water, and other liquids. Thegeneral suction unit 70 as illustrated typically includes an opening(not shown in this view) to which a vacuum hose is attached (e.g., 60 inFIG. 1), an exhaust 74, a float ball or valve 76 as a safety precautionto turn off the suction unit 70 when a liquid fills the drum 30, andlatches 54 a, 54 b for releasably securing the suction unit 70 to thecollection drum 30. Filter cage assembly 90, as well as other filtercage assemblies described herein, comprises a first end comprising a topface (not shown), and a second end comprising a bottom face 78 oppositeand spaced apart from the top face, wherein the filter cage assembly istypically attached to a motor housing or suction surface 72 of thevacuum appliance, the bottom face being available for coupling with afilter or filter assembly such as described herein. The filter cageassembly 90 extends downwardly away from and generally perpendicular tosuction surface 72 of the suction unit 70, and may be mold-formed withunit 70, or may be a separately-formed assembly that is attached to andintegrated with the suction unit 70 using any number of appropriateattachment means. The filter cage assembly 90 also typically comprises aplurality of energy-absorbing structural ribs 77 which form a supportfor the cage, and which can act to at least partially absorb impact orother stress loads applied to the cage during normal use and operationof the vacuum appliance. Ribs 77 may be formed in a parallel arrangementas illustrated, or may be oriented in a variety of other orientationswhile maintaining the desired structural support, such as inlongitudinally angled to form a “barber-pole” type arrangement aroundthe perimeter of the cage. Assembly 90 may also comprises a mountingpost or threaded bolt 80 extending downwardly from and substantiallyperpendicular to the bottom face 78 of the filter cage assembly 90, thedistal end of which may optionally further comprise anintegrally-formed, shaped head 82 which can act to further retain thefilter assembly over the filter cage assembly 90. Mounting post 80 maybe substantially cylindrical in shape, or as illustrated in FIG. 6, mayhave an hour-glass shape, such that the base of the post slopes towardsthe bottom face 78 of the filter cage assembly 90, while the leading end82 is a shaped head having a diameter greater than the diameter of thepost itself. While the shaped head at leading end 82 is illustrated tobe spherical in shape, it is by no means limited to such a shape, andcan take any number of geometric shapes, so long as the diameter of thehead is greater than the diameter of the post 80 at its narrowest point.Additionally, the hour-glass shape of the post 80 advantageouslyimproves the seal of the filter assemblies described herein against thebottom face of the filter cage, in combination with the effect of theannular retaining ring 116. In accordance with the present disclosure,the filter assemblies described herein fit over the bottom face of thefilter cage 90, wherein a portion of the mounting post 80, such asleading end 82, extends through the opening in the cap of the filterassembly and is retained in position by the elastomeric material of thecap and/or a retaining ring or means associated with the filter assemblycap 110.

When the filter assemblies of the present disclosure are constructed inthe manners disclosed herein, the filter assemblies 100 (and 300, 400and 600) have an open end opposite the integrated end cap 110 which iscircumscribed by the integral end ring 130 (see FIGS. 3-5) that isadapted to tightly interface with the exhaust section of the suctionunit 70 of the vacuum assembly. The filter unit assembly 100 shown inFIG. 6 includes a centrally-located annular hole/opening 118 in itsintegrated end cap 110, surrounded by an annular retaining ring 116 asdescribed previously. This annular hole is preferably smaller indiameter than the leading end 82 of post 80 on the filter cage. In atypical application, the post 80 (or bolt) located on the bottom face 78of the filter cage assembly 90 as shown is passed through the opening118 in the end cap 110, whereupon the hole 118 in the filter assemblyexpands so as to go over the ball (or other formed portion) on theleading end 82 of the post 80, and then contracts again to its originalsize after passing over leading end 82, so as to hold the filterassembly 100 in place on the suction unit surface 72. Stated anotherway, the opening 118 in the end cap 110, in accordance with the presentdisclosure, has an uncompressed diameter smaller than the diameter of aportion of the mounting post, such that during assembly, the opening 118expands in diameter to fit over a portion of the mounting post 80, suchas leading end 82, and thereafter contracts in diameter so as to retainthe filter assembly over the filter cage assembly 90. Due to the sizeand elastomeric characteristics of the annular retaining ring 116detailed above, the filter unit assembly 100 is tightly retained inplace over the filter cage assembly 90 without the need for additionalretaining means or mechanisms, such as a nut or similar mechanicalmeans. Upon such mounting of the filter unit assembly, the integral endring 130 acts as a gasket element to form a tight fit against a sealingsurface 72 on the suction unit 70 when the filter assemblies describedherein are retained in place as illustrated and described. Additionally,during operation of a vacuum assembly, the filter seal itself isimproved by the force of the vacuum which pulls the filter assembly intoa tight seal against the shaped filter cage mounting post 80. In certainaspects of the present disclosure, as will be described in more detailbelow with reference to FIGS. 7A-7C, when the filter assembly describedherein is coupled to the filter cage, the engagement of the projection,or mounting post, 80 with opening 118 can result in a deformation of thedeformable material such that the cap assumes a substantially conicalshape, wherein the point of the cone is such that it points eithertowards or away from the motor housing.

In accordance with the present disclosure, the general method ofattaching a filter assembly as described herein, such as filter assembly100 (or any of the other filter assemblies described herein), to afilter cage 90 of a wet/dry vacuum appliance comprises the steps ofproviding a filter cage that includes a first end and a second end and amounting projecting extending from the second end, the mountingprojection defining a mounting region; providing a filter assemblyincluding a first end, a second end, and a mounting cap positioned atthe second end of the filter, the mounting cap being at least partiallyformed of a deformable material and defining an opening; positioning thefilter assembly about the filter cage such that the filter assembly fitsover the filter cage and such that the second end of the filter assemblyis positioned closer to the second end of the filter cage than to thefirst end of the filter cage; and deforming the mounting cap to causethe mounting projection to extend through the opening in the end cap andto cause the end cap to engage the mounting region of the mountingprojection. This method is not intended to be limiting in any way, butis a general method appropriate for use with the filter assemblies andsystems described herein.

FIG. 7A illustrates a cross-sectional schematic view of a vacuum cleanermounting assembly with a filter assembly 100 of the present disclosuremounted thereto, such as that from the exploded view in FIG. 6. As showntherein, when filter assembly 100 is mounted over filter cage assembly90, at least a portion of post 80 extends above the top surface 111 ofcap 110 and annular retaining ring 116. In accordance with aspects ofthe present disclosure, in the instance where the post 80 has a formedhead 82 at its leading end, the formed head 82 preferably clears the topof ring 116 and further acts to retain the filter assembly 100 over thefilter cage 90 during normal operation of a vacuum appliance, such as awet/dry vacuum cleaner. FIG. 7A also illustrates one of severalacceptable manners in which end ring 130 mates with and forms a sealagainst sealing surface 72 of the vacuum appliances suction unit 70. Thedirectional arrows indicate the direction of vacuum force duringoperation of a vacuum appliance, illustrating again the improved filterseal formed by the use of the filter assemblies described herein,wherein the force of vacuum acts to pull the filter assembly tightlyagainst the shaped filter-cage mounting post 80. In accordance with theaspect illustrated in FIG. 7A, the engagement of mounting post 80 withopening 118 can result in very little deformation of the deformablematerial that forms and defines 118 or the cap of the filter assemblyitself, resulting in the cap of the filter assembly assuming a shapethat is substantially parallel to the bottom face 78 of the filter cage.

FIG. 7B illustrates a cross-sectional schematic view of an alternativevacuum cleaner mounting assembly with a filter of the present disclosuremounted thereto, wherein the surface of the cap 110′ is non-planar, andconical in its manner of contact with the top surface 78 of filter cage90. As shown therein, engagement of the mounting post/projection 80 withthe opening 118′ of the filter assembly causes a deformation of thedeformable material the forms the cap 110′ and defines the opening 118′,as well as the optional retaining member 116′, such that the capeassumes a substantially conical shape, the conical shape formed by thedeformable material being such that the point of the cone points in adirection towards the motor housing of the vacuum appliance (not shown).

FIG. 7C illustrates a cross-sectional schematic view of an alternativevacuum cleaner mounting assembly with a filter of the present disclosuremounted thereto, wherein the surface of the cap 110″ is in a non-planar,frusto-conical contact arrangement with the top surface 78 of filtercage 90. As shown in the figure, the frusto-conical arrangement of cap110″ with the top surface 78 of the filter cage allows for a non-planaroffset of some angle,α, between the filter assembly 100″ and the filtercage 90, while maintaining appropriate surface contact and seal suchthat vacuum may be maintained during normal operational use. As showntherein, engagement of the mounting post/projection 80 with the opening118″ of the filter assembly causes a deformation of the deformablematerial the forms the cap 110″ and defines the opening 118″, as well asthe optional retaining member 116″, such that the cap assumes asubstantially conical shape, the conical shape formed by the deformablematerial being such that the point of the cone points in a directionaway from the motor housing of the vacuum appliance (not shown).

FIGS. 8-10 illustrate alternative, yet equally acceptable embodiments ofthe present disclosure. In FIG. 8, a filter assembly 300 is illustratedin perspective view, the assembly comprising an integrated cap section310, an end ring 330 (not shown), and a cylindrically-shaped, pleatedfilter 320 intermediate between cap 310 and end ring 330. The integratedcap 310 comprises two handle portions 312, 314 and a formed hole 316 inthe center of the cap. As with the filter assemblies described above,the handle portions 312 and 314 extend partially over the top and edgesof the pleated filter 320, and act to allow for providing the user witha gripping surface to aid in filter removal from the filter cage of avacuum appliance when changing filters. As illustrated in FIG. 8, thehole 316 in cap 310 is formed in a general annular, taurus-like shape ofsuch a size, shape and internal diameter that the ball or end flange ona filter cage can be forced up and through the hole 316 so as retain thefilter assembly on the filter cage and seated against the base of thevacuum appliance. As in the embodiments described above, the elasticityand physical characteristics of the material forming the cap 310, and inparticular the hole 316, allows the end cap 310 to become sealed aroundthe flange of a filter cage (not shown) after installation.

FIGS. 9 and 10A-10B illustrate a further embodiment of the filterassemblies of the present disclosure. A perspective view of such afilter assembly 400 is illustrated in FIG. 9, the assembly 400comprising a fully integrated cap 410, flanges 412 and 414, acylindrically-shaped, pleated filter 420, and an integrated end ring 430spaced opposite and parallel to cap 410, such that the pleated filter420 is intermediate therebetween. Cap 410 may be made from any of thepolymeric materials described above, preferably from a polyurethane suchas an ELASTOPLEX® (available from B.A.S.F. Corporation) polymer or foam.Fully integrated cap 410 extends across the entire top diameter of thefilter 420, and integrally retains filter 420 in part via lip 405 whichis a formed part of cap 410, and which both circumscribes the outer edgeof cap 410 and extends a distance d₆along the outer edge of filter 420,perpendicular to the top face of cap 410. Flanges 412 and 414, as shownherein, may be of any appropriate shape and size, such that they may begripped by the user in installing or removing the filter 400, andpreferably extend upwardly from the top face 402 of cap 410.Additionally, while flanges 412 and 414 may be formed separately andattached to the top face 402 using any appropriate methods, such asthrough the use of adhesives, flanges 412 and 414 are preferablyintegrally formed with the cap 410. FIG. 10A illustrates a cut-away sideview of the assembly 400 of FIG. 9, taken along line 9-9, as it appearseither during removal from a vacuum filter cage 500, or alternatively,and as described above with reference to a separate filter assembly 100,engagement of the mounting post/projection 502 with the opening 418 ofthe filter assembly may cause a deformation of the deformable materialthe forms the cap 410 and defines the opening 418, such that the capassumes a substantially conical shape, the conical shape formed by thedeformable material being such that the point of the cone points in adirection towards the motor housing of the vacuum appliance. As is moreclearly seen in this figure, the projection 502, integrally formed withthe top face 501 of cage 500 associated with a vacuum appliance (notshown) extends through opening 418 in integrated cap 410 in a manner asdescribed above, wherein the opening 418 has an uncompromised diametersmaller than a diameter of a portion of the projection 502, or theleading end 504 thereof, such that, during assembly, the opening 418expands in diameter to fit over a portion of the projection 502, andthereafter contracts in diameter so as to retain the filter over thecage 500.

FIG. 10B illustrates a top-view of an alternative aspect of the filterof FIG. 9, wherein the assembly comprises an integrated, top cap 410′,two (or more) upwardly extending flanges 412 and 414 formed on the topface of cap 410′, a pleated filter 420, and a hole 418 formed in thecenter of cap 410′ and surrounded by an integrally-formed, taurus-shapedretaining ring 416. Similar to the filter assemblies described above,the physical characteristics (e.g., elasticity) of the material formingthe top cap 410′ and/or the retaining ring 416 circumscribing the hole418 allows the end cap 410′ to seal around the flange of a filter cageafter installation over a filter cage in a vacuum appliance. The aspectillustrated in FIG. 10B differs from that shown in FIG. 9 in that thecap 410′ has a top diameter that is less than the diameter of the filter420, such that the ends of filter 420 extend outwardly past the edge ofcap 410′.

FIG. 11 illustrates a further aspect filter assembly embodiment 600 ofthe present disclosure, comprising a plurality of handles 612, 614. Asillustrated in the figure, the assembly 600 comprises a top cap portion610, a lower end ring 630, and a pleated filter 620 spaced intermediatebetween the cap 610 and the lower end ring 630, wherein the cap 610 andthe end ring 630 are bonded to the filter 620. Top cap portion 610comprises an annular hole 616 extending through its entire thickness, aswell as an optional, taurus-shaped ring 618 circumscribing the annularhole 6516. As suggested in accordance with the embodiments above, ring618 may be integrally-formed into the top face 611 of cap 610, or it maybe attached by any number of other appropriate attachment methods, suchas by adhesives or mechanical attachments. As illustrated in the figure,top cap 610 (and/or bottom ring 618) may have an outer dimension d₁ thatis greater than the outer dimension d₃ of the filter 620, although it isequally acceptable to have an arrangement wherein d₁ is substantiallythe same as d₃, or wherein d₃ is greater than d₁, as discussedpreviously herein. As above, the top and bottom portions 610, 630 may bemade of any appropriate material, such as polymeric materials includingany number of plastics, metals such as steel, or elatomeric or rubbermaterials, provided that the materials can be bonded to the filter 620,and have a flexibility such that the cap portion 610 can fit over theball on the leading end of the filter cage stem and form a seal, asdescribed above. The embodiment shown in FIG. 11 comprises four handleportions 612 a, 612 b, 614 a, 614 b, which as drawn extend outwardlypast the outer diameter of the filter. Although handle portions 612 a,612 b are illustrated as being generally diametrically opposed tohandles 614 a, 614 b, respectively, this is not necessary, and theplurality of handles may be non-diametricaly opposed, as desired.

The filter assemblies, and systems employing such filter assembliesdescribed herein offer several advantages over filters for vacuumappliances, especially wet/dry type vacuum cleaners, currently on themarket. In particular, due to the small amount of polymeric materialused in forming the filter assemblies, the presently disclosed filterassemblies are cheaper and more readily produced. Other advantagesinclude less time to replace or clean the filter assembly, and nocumbersome mechanical attachment mechanisms are involved, thuseliminating the possibility of lost parts otherwise necessary forattachment of the filter. Additionally, the filter assemblies describedherein may be readily retro-fit to existing vacuum appliances already inthe market and requiring these types of filters. Finally, as indicatedabove, the characteristics—both physical and mechanical—of the end capportion of the filter assemblies allows for an automatic seal of thefilter assembly onto the mounting post of the filter cage of a vacuumappliance, such seal providing a secure retaining of the filter assemblyduring normal operation, as well as during dropping, jarring or otherunexpected events.

FIGS. 12A and 12B illustrate alternative filter cage assemblies for usein association with the filter assemblies described herein, which allowfor the retrofitting of existing assemblies to the instant filterassemblies (FIG. 12A), and the conversion of filter cages as describedherein to allow for the use of standard filter assemblies and threadednut retaining means (FIG. 12B), as desired. FIG. 12 A illustrates afilter cage assembly 700 comprising a top surface 790 having a threadedstem 780 extending upwardly therefrom, and a plurality of openings 791to provide for the flow of air or other media downstream of the filterthrough the openings and into the mounting assembly for a vacuum, andthereafter subsequent exhaust, as is known in the art. These openings791 are formed by one or more longitudinally angled rib members 794 thatare formed at a zero or non-zero angle to the longitudinal axis of thefilter cage, as well as one or more circumferential ribs 792 extendingaround, and substantially circumscribing the cage 700. Optionally, theouter surface of either the longitudinally angled ribs 794 or thecircumferential ribs 792 may extend outward from the outer surface ofthe filter cage so as to allow the filter (not shown) to slide over thecage without interference from the circumferential ribs. In accordancewith this embodiment, the cage assembly may comprise a separate, formedstem 750 having sloped or otherwise shaped sides and a polygonal orspherical head, as well as interior grooves 752 formed substantiallycentral within, such as by a machining tool. Stem 750 is preferablysolid, and may be made of any appropriate material, such as plastic orother suitable polymers, or a metal, as appropriate. In use, stem 750may be simply threadably attached to stem 780 of filter cage assembly700 via the threads on stem 780, such that it mounts substantially flushwith top surface 790. In this manner, an older-style vacuum appliancemay be readily adapted for use with the filter assemblies describedherein.

FIG. 12B illustrates yet another alternative filter cage assembly 800comprising a filter cage assembly 800, similar to that described inrelation to FIG. 12A, and comprising a top surface 890 having a formed,polygonal stem 850 extending upwardly therefrom, and a plurality ofopenings 891 to provide for the flow of air or other media downstream ofthe filter through the openings and into the mounting assembly for avacuum, and thereafter subsequent exhaust, as is known in the art. Theseopenings 891 are formed by one or more longitudinally angled rib members892 that are formed at a zero or non-zero angle to the longitudinal axisof the filter cage, as well as one or more circumferential ribs 894extending around, and substantially circumscribing the cage 800.Optionally, the outer surface of either the longitudinally angled ribs892 or the circumferential ribs 894 may extend outward from the outersurface of the filter cage so as to allow the filter (not shown) toslide over the cage without interference from the circumferential ribs.The assembly illustrated in FIG. 12B further comprises adapter 860suitable for converting a filter cage assembly from those such asdescribed herein to a standard filter cage assembly having a threadedstem. Adapter 860 is preferably a solid piece of formed, extruded, ormachined material (including but not limited to plastic, polymericmaterials, elastomers, metal, and the like) having two or more spacedapart sides 863, 865, a top face 862, and a bottom face 864 which in usemakes contact with top surface 890 of filter cage assembly 800. The topface 862 of adapter 860 comprises a threaded stem 866. Adapter 860further comprises a shaped, interior portion 870, formed in anappropriate shape such that in use, adapter 860 may be simply pusheddownward in the direction of the arrow onto and over shaped stem 850,such that the bottom face of the adapter 864 makes contact with top face890 of the cage.

FIGS. 12C-12E illustrate further, alternative filter cage assemblies 880and 880′ in accordance with aspects of the present disclosure andsuitable for use in association with the filter assemblies of thepresent disclosure. FIG. 12C illustrates a partial perspective view offilter cage assembly 880 comprising a generally planar surface 882 ofthe bottom end of the cage assembly 880, having a formed projection 884,such as a mounting post or stem, extending upwardly therefrom.Projection 884 may be shaped as shown to include a neck region 883 and ahead portion 887, such that neck region 883 is intermediate between thesurface 882 of the cage assembly, and the head portion 887. As furthershown in FIG. 12C, projection 884 may further comprise one or moreoutwardly-projecting ribs 885 formed into and circumscribing neck region883, such ribs acting to further retain filter assemblies of the presentdisclosure when they are inserted into place over cage assembly 880 asit is associated with a vacuum appliance, such as described hereinabove. Cage assembly 880 also comprises one or more longitudinallyangled rib members 886 that are formed at a zero or non-zero angle tothe longitudinal axis of the filter cage, as well as one or morecircumferential ribs 888 extending around, and substantiallycircumscribing the cage 800. These ribs in combination define aplurality of openings 891 as shown in the figure, which as describedabove provide for the flow of air or other media downstream of thefilter through the openings and into the mounting assembly for a vacuum,and thereafter subsequently exhaust the air. Optionally, the outersurface of either the longitudinally angled ribs 894 or thecircumferential ribs 888 may extend outward from the outer surface ofthe filter cage so as to allow the filter (not shown) to slide over thecage without frictional interference from the circumferential ribs.

FIG. 12D illustrates a perspective view of a further, alternative filtercage assembly 880′ in accordance with aspects of the present disclosureand suitable for use in association with the filter assemblies of thepresent disclosure. Similar to the cage assembly 880 of FIG. 12C,assembly 880′ includes a generally planar bottom surface 882, as well aslongitudinal and circumferential rib members 886 and 888 (respectively)which in combination define openings 891 as discussed previously. Cageassembly 880′ also comprises a formed projection 884, such as a mountingpost or stem, extending outwardly away from surface 882. Projection 884may be shaped as shown to include a shoulder region 881 elevating theprojection from surface 882, neck region 883 and a head portion 887,such that neck region 883 is positioned between the shoulder region 881of the projection 884, and the head portion 887. As also illustratedtherein, neck region 883 may further comprise one or more rib members885 circumscribing the neck region 883, and which may be useful inretaining filter assemblies in accordance with the present disclosure inplace over cage 880′. The head portion 887 as illustrated in the figuremay be semi-hemispherical in shape as shown, although any shape may beused as appropriate, and may also include one or more formed indents 889which may act as grips for the user during installation and removal of afilter assembly as described herein onto and over the cage 880′. FIG.12E is a cross-sectional view of the filter cage assembly 880′ of FIG.12D, taken along line 12-12, and illustrating more clearly the spatialrelationship of the head, neck, should and rib portions of projection884 as it extends outwardly away from the surface 882 (typically thebottom surface) of the cage.

In further aspects of the present disclosure, the center sealingassemblies described herein, comprising an annular center holecircumscribed by a collar which adds strength and provides for anelastomeric retention of the filter assembly over a filter cage of avacuum appliance, may be provided in a separate element apart from thefilter itself. In example, a filter assembly may comprise a firstportion and a second portion, wherein the first portion comprises ashaped filter, optionally further comprising an end ring for sealinglyengaging with the inner face of a vacuum motor mount. In accordance withthis aspect, the second portion may comprise a separate cap portionhaving a centrally located annular hole extending therethrough and aretaining ring or collar circumscribing the annular hole. During use,the first portion comprising the filter would be placed over the filtercage of the vacuum assembly, whereafter the separate, second portionwould then be placed over the top of the first filter portion, such thatthe mounting stem or post on the bottom face of the filter cage extendsthrough the annular hole in the cap portion in a manner as describedpreviously herein. That is, the annular hole preferably has a diameterthat is smaller than the diameter at least a portion of the mountingpost, for example a diameter of the leading end of the mounting stem orpost on the filter cage, (which may or not be hour-glass shaped), suchthat as the second portion is pushed over at least a portion of themounting stem, the annular hole expands to go over the stem, and thencontracts back to its original diameter as the second portion sealsagainst the bottom face of the filter cage, thereby sealably engagingthe first filter portion against the lower part of the vacuum head. Inaccordance with this aspect, similar to aspects described above, theretaining ring or collar on the second portion can aid in holding thesecond portion in place against the first filter portion by constrictingagainst the mounting stem.

Several of the above-described embodiments of the present disclosure areillustrated generally in FIGS. 13A-13E. FIGS. 13A, 13B and 13Cillustrate top views of a cap section 900, 900′, and 900″, respectively,each having a differently shaped hole, orifice, or opening (902, 904,906) within and extending through, the cap sections. For example, inFIG. 13A, opening 902 is generally keyhole-shaped, and optionallyoff-center, such that in use the stem of the filter cage assembly maycome up and through the opening 902, after which the entire filterassembly is shifted in such a manner as to lockably engage the stem ofthe filter cage and the filter assembly, thus making the use of aretaining ring as described herein optional or unnecessary. In FIG. 13A,opening 904 is a plurality (2 or more) of slits in the cap section 900′,which allow for the stem of the filter cage assembly to extend up andthrough the top cap section of the filter assembly, while still allowingfor the formation of a suitable seal of the filter assembly against thefilter cage. Similarly, in FIG. 13C, cap section 900″ comprises a singleslit 906 extending through a portion of the cap 900″, and which allowsthe stem of a filter cage to extend up and through the cap section 900″of a filter assembly of the present disclosure. Advantageously, theembodiment illustrated in FIG. 13C allows for the use of filters such asdescribed herein with a range of different vacuum appliances havingdifferently-placed and shaped filter cages. While integrally-formedhandles and support members, such as described above, are not includedin these figures for purposes of clarity, their optional inclusion withthese embodiments is contemplated as described herein.

In FIG. 13D, a partial perspective view of an alternative embodiment ofa filter assembly in accordance with the present disclosure isillustrated, which comprises a cap section 910, an end ring 930 (notshown), and, a generally cylindrically-shaped, pleated filter 920intermediate between cap 910 and end ring 130 and extending in a closed,circumferential path and which includes a closed, interior path. The cap910 may further, optionally comprise a formed hole 952 in the center ofthe cap, centrally-formed opening 952 extending from the top surface 950of cap 910 through the cap to the closed, interior airflow path formedby filter 120. While opening 952 is illustrated to be substantiallyannular herein, it is contemplated that it may of any number of shapesand styles, as described herein. As also illustrated in FIG. 13D, thefilter assembly may comprise a separate retaining member 960 for usewith retaining the filter assembly in association with a filter cage ofa vacuum assembly. In general, it is envisioned that in use, the filter920 would be placed over the filter cage of a vacuum appliance (notshown), cap 910 would then be placed over the top of the filter, suchthat the stem of the filter cage extends up and through opening 952,after which retaining member 960 would be slid down and over the stem,and hold the assembly in place. In accordance with the presentdisclosure, it is envisioned that the cap 110 may also optionallycomprise a plurality of integrally-formed support struts (illustrated inhashed lines), to add structural integrity to the cap section 910, aswell as one or more optional handles (not shown).

FIG. 13E illustrates a further embodiment of the present disclosure,similar to that shown in FIG. 13D, but wherein the retaining member 988is connected to the top face 980 of cap 970 by a flexible member 987,which may be made of the same, or different, material as that which thecap 970 itself is made from. In use, once the filter assembly has beenplaced over the filter cage of the vacuum appliance, such that the stemof the filter cage extends upward through opening 986, the user may thenextend retaining member 988, via flexible member 987, up and over thestem, so as to hold the entire filter assembly in place. Advantageously,this embodiment allows for the use of an optional filter retainingmember 988 which is directly connected to the top face 980 of the filtercap 970, and which can be used or not used, depending upon the specificvacuum appliance with which the assembly is being associated. Similar tothe caps described herein above, cap 970 may optionally comprise one ormore integrally-formed support struts (illustrated in hashed lines), inorder to add structural strength and integrity to the cap section 970,as well as one or more optional handles 982, 984, as appropriate.

FIGS. 14A and 14B illustrate a further embodiment of the presentdisclosure, wherein the snap-on filter assembly 1000 is shown without anopening or orifice, but rather with a stem-cap 1040 integrally formedwith the filter cap itself. Filter assembly 1000 comprises anintegrally-formed integrated cap section 1010, spaced-apart, annular endring 1030, and a generally cylindrically-shaped, pleated filter 1020intermediate between cap 1010 and end ring 1030, the filter 1020extending in a generally closed, circumferential path and which includesa closed, interior path (not shown). As illustrated in the Figure, theintegrated cap 1010 may further, optionally comprise one or more (twoare shown) integrally-formed handles 1012, 1014 as shown and describedpreviously, a formed edge or rim 1017 circumscribing the exterior of thecap 1010, and an opening 1041 (not shown), such as a formed or moldedhole or other appropriate opening, formed in the cap, wherein theopening 1041 is covered by stem cover means 1040 which extends upwardlyfrom the top surface 1011 of cap 1010. As can be seen in FIG. 14B,described in more detail below, opening 1041 extends from the topsurface 1011 of cap 1010 through the cap to the closed, interior airflowpath 1050 formed by filter 1020. As further illustrated in FIG. 14A, thecap 1010 may also optionally comprise a plurality of integrally-formedsupport struts 1015, to add structural integrity to the cap section1010. As illustrated in the Figure, struts 1015 may extend radiallyoutward from the stem cover means 1040 towards, and optionally integratewith, rim 1017 of the cap. While two handle-portions 1012 and 1014 areillustrated, it will be recognized that the filter assemblies describedherein may have no handles, a single handle, or more than two handles,which may be oriented in a variety of manners, such as perpendicular tothe top face of the cap portion or in a plane substantially in alignmentwith the top surface of cap 1010, without limitation.

As illustrated more clearly in FIG. 14B, which is a cross-sectional viewof the filter assembly 1000 of FIG. 14A, taken along line 14-14, thestem cap or stem cover means 1040 comprises an outer portion 1044, aninterior opening 1041 opening into the central region of the filterassembly 1000 and opposite the top face of cap 1011, and a shaped innerregion 1042 which may optionally further comprise an inner grippingportion or gripping means 1046. The stem cover means 1040 is arranged tobe placed over the stem or stem head (not shown) of the filter cage whenthe filter assembly 1000 is engaged with a vacuum appliance as describedabove. In accordance with one aspect of this embodiment, the stem covermeans 1040 may be retained in position by means of the shaped innerregion 1042, alone or in combination with one or more optional grippingmeans 1046 which can act to grip the filter cage stem or stem head andretain the filter assembly 1000 in place, engaged with the vacuumappliance. In accordance with certain aspects of this embodiment, thecover means 1040 may be substantially hollow, having a shaped innerregion 1042 whose shape corresponds to the filter cage stem with whichit will interact and engage. While the cover means 1040 is illustratedto be substantially cylindrical in shape, it may have a domed orotherwise shaped outer section 1044, which is opposite the opening 1041in the cover means. The optional gripping means 1046 may comprise one ormore resilient arms or equivalent gripping means so as to more tightlyengage the stem or stem head of a filter cage, particularly when thestem is not shaped, but rather is of standard, cylindrical (threaded ornot) design.

In an exemplary typical method of use, the filter assembly 1100 issimply pushed down onto and over an exposed filter cage assembly portionof a vacuum appliance, such as the type illustrated generally in FIG. 6herein, wherein interior air flowpath 1050 defined at least in part byfilter 1020 circumscribes the exterior of the filter cage assembly. Theassembly 1100 is pushed down such that stem cover 1040 is simply pushedonto the exposed and downwardly-extending filter cage stem head. Theshaped inner region 1042 of the stem cover 1040 is just smaller than theouter width of the cage stem head, so that when pushed onto a vacuumappliance cage stem, the inner region 1042 deforms slightly and gripsthe cage stem. Alternatively, and equally acceptable, in the event thatone or more gripping means are included within stem cover 1040, theinner region 1042 will be slightly larger than the outer width of thecage stem head, so that when pushed onto a vacuum appliance cage stem,the gripping means 1046 deform slightly and thereby grip the cage stem.Tension between the shaped inner region 1042 and the cage stem, orbetween the gripping means 1046 and the cage stem will work to retainthe filter assembly 1000 in place and engaged with a vacuum appliance,even when vacuum is not being applied.

FIG. 15 illustrates a perspective view of a further embodiment of thepresent disclosure, the design of filter assembly 1100. Filter assembly1100 is a design variant of the filter assembly 100 described herein,and which comprises an integrally-formed integrated cap section 1110,spaced-apart, annular end ring 1130, and a generallycylindrically-shaped, pleated filter 1120 intermediate between cap 1110and end ring 1130, the filter 1120 extending in a generally closed,circumferential path and which includes a closed, interior path (notshown). As illustrated in the Figure, the integrated cap 1110 mayfurther, optionally comprise one or more (two are shown)integrally-formed handles 1112, 1114 as shown, a formed edge or rim1117, and an opening 1118, such as a formed or molded hole, slit, orother appropriate opening, formed either in the center of the cap 1110,or formed off-center of the central, vertical axis of the filter, asappropriate. Opening 1118 extends from the top surface 1111 of cap 1110through the cap to the closed, interior airflow path formed by filter1120. The cap 1110 may also optionally comprise a plurality ofintegrally-formed support struts 1115, to add structural integrity tothe cap section 110. As illustrated in the Figure, struts 1115 mayextend radially outward from the opening 1118 towards, and optionallyintegrate with, rim 1117 of the cap. In a non-limiting manner, and asshown in the figure, the handle portions 1112 and 1114 may besubstantially diametrically opposed in orientation, and can extendpartially over the top and edges of the pleated filter 1120, so as toallow for providing the user with a gripping surface to aid in filterremoval from the filter cage of a vacuum appliance when changingfilters. While two handle-portions 1112 and 1114 are illustrated, itwill be recognized that the filter assemblies described herein may haveno handles, a single handle, or more than two handles, which may beoriented in a variety of manners, such as perpendicular to the top faceof the cap portion or in a plane substantially in alignment with the topsurface of cap 1110, without limitation. As also illustrated in FIG. 15,the opening 1118 in cap 1110 can be optionally circumscribed by anintegrally- or non-integrally formed annular retaining ring 1116 havinga general taurus-like (donut) shape (or other shape, as desired orappropriate) of such a size, shape and internal diameter that the ballor lead-end flange on the leading end of a mounting shaft on a vacuum'sfilter cage can be forced up and through the opening 1118, in a manneras discussed herein above, so as to retain a filter assembly of thepresent disclosure on the filter cage and seated against the base of thevacuum appliance. If retaining ring 1116 is integral, it will be formedinto cap 1110 as part of the manufacturing process. In the event thatring 1116 is non-integral and is a separate element of the filterassembly, it may be attached to the top surface 1111 through any numberof appropriate chemical (e.g., glue) or mechanical methods, withoutlimitation.

In FIG. 16, a perspective view of the design of a filter assembly 1200is illustrated, in a manner similar to that presented in FIG. 15. Asshown therein, the filter assembly 1200 comprises an integrally-formedan integrated cap section 1210, an end ring 1230, and, a generallycylindrically-shaped, pleated filter 1220 intermediate between cap 1210and end ring 1230 and extending in a closed, circumferential path andwhich includes a closed, interior path (not shown), similar to thedesign of filter assembly 100 described above. As illustrated in theFigure, the integrated cap 1210 may further, optionally comprise one ormore (two are shown) integrally-formed handles 1212, 1214 as shown, aformed intermediate rim 1217, an opening 1218, such as a formed ormolded hole, slit, or other appropriate opening, formed either in thecenter of the cap 1210, or formed off-center of the central, verticalaxis of the filter, as appropriate. Opening 1218 extends from the topsurface 1211 of cap 1210 through the cap to the closed, interior airflowpath formed by filter 1220. The cap 1210 may also optionally comprise aplurality of integrally-formed support struts 1215, to add structuralintegrity to the cap section 110. As illustrated in the Figure, struts1215 may extend radially outward from the opening 1218 towards, andoptionally integrate with, intermediate rim 1217 of the cap. As alsoshown in FIG. 16, cap 1210 of filter 1200 may further comprise an outeredge region 1219 that substantially circumscribes the rim 1217, andextends outwardly to a distance such that its outer edge 1222 issubstantially in the same plane as, and does not extend past, the outeredge (diameter d₃) of the filter 1220. In a non-limiting manner, and asshown in the figure, the handle portions 1212 and 1214 may besubstantially diametrically opposed in orientation, and can extendpartially over the top and edges of the pleated filter 1220, so as toallow for providing the user with a gripping surface to aid in filterremoval from the filter cage of a vacuum appliance when changingfilters. While two handle-portions 1212 and 1214 are illustrated, itwill be recognized that the filter assemblies described herein may haveno handles, a single handle, or more than two handles, which may beoriented in a variety of manners, such as perpendicular to the top faceof the cap portion or in a plane substantially in alignment with the topsurface of cap 1110, without limitation. As also illustrated in FIG. 16,the opening 1218 in cap 1210 can be optionally circumscribed by anintegrally- or non-integrally formed annular retaining ring 1216 havinga general shape of such a size, shape and internal diameter that theball or lead-end flange on the leading end of a mounting shaft on avacuum appliance's filter cage can be forced up and through the opening1218, in a manner as discussed herein above, so as to retain a filterassembly 1200 of the present disclosure on the filter cage (not shown)and seated against the base of the vacuum appliance. If retaining ring1216 is integral, it will preferably be formed into cap 1210 as part ofthe manufacturing process. In the event that ring 1216 is non-integraland is a separate element of the filter assembly, it may be attached tothe top surface 1211 through any number of appropriate chemical (e.g.,glue) or mechanical methods or mechanical means (such as by a flexiblehinge portion of elastomeric material), without limitation, as describedabove.

The invention has been described in the context of preferred and otherembodiments and not every embodiment of the invention has beendescribed. Obvious modifications and alterations to the describedembodiments are available to those of ordinary skill in the art. Thedisclosed and undisclosed embodiments are not intended to limit orrestrict the scope or applicability of the invention conceived of by theApplicants, but rather, in conformity with the patent laws, Applicantsintends to protect all such modifications and improvements to the fullextent that such falls within the scope or range of equivalent of thefollowing claims.

What is claimed is:
 1. A filter for use with a wet/dry vacuum cleaner,the filter comprising: a central longitudinal axis; a cap having a topface and an opposite bottom face, and an annular hole of a diameter lessthan the diameter of the cap extending through the center of the capabout the central longitudinal axis of the filter, the cap including oneor more integrally formed handles, the one or more handles extendingover the outer edge of the filter such that the diameter between theouter edges of the handles is greater than the outer diameter of thefilter; a support strut on the top face of the cap; and a filterpositioned below the cap and extending in a circumferential path thatforms a closed, interior path, the filter being integrally formed withthe cap portion to form a single filter assembly, wherein the centrallylocated annular hole is circumscribed by a retaining structure, whereinthe cap is comprised of a flexible material bonded to the filter, andwherein when the cap is in association with a filter cage of the wet/dryvacuum appliance, the cap seals on a plane above the top surface of thefilter.
 2. The filter of claim 1, wherein the opening is non-centrallylocated.
 3. The filter of claim 1, wherein the opening defines anunobstructed region.
 4. The filter of claim 1, wherein the cap furthercomprises one or more integrally formed handles.
 5. The filter of claim4, wherein the one or more integrally formed handles are located in thesame plane as the top surface of the cap.
 6. The filter of claim 4,wherein the one or more integrally formed handles are diametricallyopposed.
 7. The filter of claim 4, wherein the one or more integrallyformed handles are non-diametrically opposed.
 8. The filter of claim 1,wherein the cap further comprises one or more handles which aresubstantially perpendicular to the top surface of the cap.
 9. The filterof claim 1, wherein the support strut on the top face of the cap. 10.The filter of claim 1, wherein the top face is substantially planar. 11.The filter of claim 1, wherein the filter is a cylindrically-shaped,oval-shaped, conically shaped, elliptical, or rectangular-shaped filter.12. The filter of claim 1, wherein the filter is comprised of paper,cloth, polymeric materials, fibrous materials, or HEPA-type materials.13. The filter of claim 12, wherein the filter further comprise at leastone biostatic and/or biocidal agent.
 14. The filter of claim 1, whereinthe flexible material is a metal, a polymeric material, or anelastomeric material.
 15. The filter of claim 14, wherein theelastomeric material is a two-part polyurethane foam material having anelongation as determined by ASTM D-1564 of from about 90% to about 200%.16. The filter of claim 1, wherein the retaining ring is integrallyformed with the cap.
 17. The filter of claim 1, wherein the retainingring is not integrally formed with the cap.
 18. The filter of claim 1,further comprising an annular end ring circumscribing the filter andlocated such that the filter is intermediate between the cap and the endring.
 19. A filter for use with a wet/dry vacuum appliance, the filtercomprising: a cap having a centrally-located opening extendingtherethrough; an annular end ring; a filter positioned between the capand the end ring and extending in a circumferential path that forms aclosed, interior region; and a stem cover defining an inner regioncircumscribing the centrally-located opening, wherein the cap and theend ring are comprised of a flexible material bonded to the filter. 20.The filter of claim 19, wherein the centrally-located opening iscircumscribed by a retaining ring.
 21. The filter of claim 20, whereinthe retaining ring is integrally formed with the cap.
 22. The filter ofclaim 20, wherein the retaining ring is not integrally-formed with thecap.
 23. The filter assembly of claim 19, wherein the shaped innerregion further defines an inner gripping portion capable of engaging afilter cage stem.